Your Christian walk influences people and that includes your family. Refusing to forgive has dire consequences. If you have a root of bitterness that springs up inside of you because you don't forgive somebody, you will influence your family and it won't be for the good. So if you need to forgive someone, just do it and don't think about it. Why? Because forgiveness is an act of the will, not an act of emotion. If you delay and start considering it, the devil's going to talk you out of it.